Similar presentations

2 Copy it, adapt it, use it – but acknowledge the source!Copyright & DisclaimerCopy it, adapt it, use it – but acknowledge the source!CopyrightIncluded in the SSWM Toolbox are materials from various organisations and sources. Those materials are open source. Following the open-source concept for capacity building and non-profit use, copying and adapting is allowed provided proper acknowledgement of the source is made (see below). The publication of these materials in the SSWM Toolbox does not alter any existing copyrights. Material published in the SSWM Toolbox for the first time follows the same open-source concept, with all rights remaining with the original authors or producing organisations.To view an official copy of the the Creative Commons Attribution Works 3.0 Unported License we build upon, visit This agreement officially states that:You are free to:Share - to copy, distribute and transmit this document Remix - to adapt this document. We would appreciate receiving a copy of any changes that you have made to improve this document.Under the following conditions:Attribution: You must always give the original authors or publishing agencies credit for the document or picture you are using.DisclaimerThe contents of the SSWM Toolbox reflect the opinions of the respective authors and not necessarily the official opinion of the funding or supporting partner organisations.Depending on the initial situations and respective local circumstances, there is no guarantee that single measures described in the toolbox will make the local water and sanitation system more sustainable. The main aim of the SSWM Toolbox is to be a reference tool to provide ideas for improving the local water and sanitation situation in a sustainable manner. Results depend largely on the respective situation and the implementation and combination of the measures described. An in-depth analysis of respective advantages and disadvantages and the suitability of the measure is necessary in every single case. We do not assume any responsibility for and make no warranty with respect to the results that may be obtained from the use of the information provided.

3 How it can optimize SSWM Operation and maintenance Applicability ContentsConceptHow it can optimize SSWMOperation and maintenanceApplicabilityAdvantages and disadvantagesReferences3

4 1. ConceptBackgroundA Soak pit, also known as soakaway or leach pit, is a covered, porous- walled chamber that allows water to slowly soak into the ground.Pre-settled wastewater or greywater effluent from an upstream collection and storage/treatment facility or collected stormwater is discharged to the underground chamber from where it infiltrates into the surrounding soil.4

5 Functional Design of a Soak Pit Source: TILLEY et al. (2008)1. ConceptFunctional DesignSoak pits can be either left empty and lined with porous material to provide support and prevent collapse, or they are unlined and filled with coarse rocks and gravel to provide support and to prevent collapsing.A layer of sand and fine gravel has to be spread across the bottom to support disperse the flow.Functional Design of a Soak Pit Source: TILLEY et al. (2008)5

6 Functional Design of a Soak Pit Source: TILLEY et al. (2008)1. ConceptFunctional DesignThe depth of a soak pit should be between 1.5 and 4 m. The bottom of the soak pit has to be more than 1.5 m above the ground water table.As pre-treated wastewater and greywater percolates through the soil from the soak pit, small particles are filtered out by the soil matrix and organics are digested by micro-organisms.The wastewater effluent is absorbed by soil particles and moves both horizontally and vertically through the soil pores.Functional Design of a Soak Pit Source: TILLEY et al. (2008)6

7 2. How it can optimise SSWMImplementation and use of Soak Pit can help in optimizing your local water management and sanitation system and make it more sustainable by:Offering a cost-efficient opportunity for a partial wastewater treatmentProviding a relatively safe way of discharging pre-treated wastewater into the environmentRecharging groundwater bodies7

8 3. Operation and MaintenanceA well-sized soak pit should last for about 3-5 years without maintenance.To extend the life of a soak pit, care should be taken to ensure that the effluent has been clarified and/or filtered well to prevent excessive build up of solids.The soak pit should be kept away from high-traffic areas so that the soil above and around it is not compacted.To allow for future access, a removable (preferably concrete) lid should be used to seal the pit until it needs to be maintained.Particles and biomass will eventually clog the pit and it will need to be cleaned or moved.8

9 4. ApplicabilityA soak pit does not provide adequate treatment for raw wastewater and this technology should only be considered for discharging pre- settled wastewater or greywater as well as rainwater.Soak pits are appropriate for rural and peri-urban settlements.They are not appropriate for areas that are prone to flooding or have high groundwater tables.Soak pits are best suited to soils with good absorptive capacity, whereas clay soils as well as hard packed or rocky soils are not appropriate.9

10 5. Advantages and DisadvantagesCan be built and repaired with locally available materialsSmall land area requiredLow capital cost and low operating costSimple technique for all users(TILLEY et al. 2008)Disadvantages:Pre-treatment of the incoming effluent is required to prevent clogging, although eventual clogging is inevitableMay negatively affect soil and groundwater properties(TILLEY et al. 2008)10